Simon King, who once ran Tesco's operations in Turkey and South Korea, is to join Asda as chief operating officer with responsibility for all retail and supply chain operations, including distribution and customer service. His appointment completes the reshuffle of the top management team after Andy Bond's move to become part-time chairman in April.

King is based in Saudi Arabia at the supermarket chain Panda, the largest in the kingdom, and will start his new role on 10 January. Until last year, he worked for Tesco in Turkey. He has also headed a number of Tesco's international operations including South Korea, the Czech Republic, Slovakia, Poland and Hungary. He has also worked for Safeway.

Clarke and King will have to steer Asda, Britain's second-largest retailer, back to the front of the sector. It has lagged behind its big four supermarket rivals and reported two quarters of falling sales, losing market share to Sainsbury's and Waitrose. Clarke's predecessor, Bond, previously set out goals for Asda to overtake Tesco to become the market leader in general merchandise, by opening home and clothing stores, and to leapfrog Sainsbury's to become No 2 in food.

However, it still has a long way to go. A recent report by the Institute of Promotional Marketing showed that Asda was the second worst of the big chains at meeting customer demand, with a quarter of shoppers who made a special trip to the supermarket to buy something on promotion unable to find it.